The spring allergy season is upon us. Pollen counts are skyrocketing, sinuses are swelling, and for some of us other symptoms are creeping in as well. If you’ve experienced a “brain fog” characterized by dizziness, imbalance and fatigue during allergy season and wondered about the connection between the pollen you’re inhaling and the mental murkiness, you’re not alone. Science has been working the case, and although we don’t have a clear picture just yet, we’re beginning to understand more about what happens in our brains when pollen is in the wind.

The basics of this story involve allergens (whatever assortment of pollen, mold and dander sets you off) and the immune system. If you’re among the 30% or so of the population with seasonal allergies, your body responds to allergens as an assault and your immune system reacts by producing histamines, compounds that cause muscle contractions and blood vessel dilation. Later into the reaction, your body releases proteins called cytokines that signal the surrounding tissue to brace against the offenders.

All of this plus the activity of a few more chemicals results in inflammation, which we feel in our sinuses, nasal membranes, throats, eyes and lungs. Some of us are more sensitive to particular allergens (freshly cut grass is olfactory heaven for some, hell for others), and the severity of reactions varies, from annoying to life threatening.

What makes matters worse is suffering through those symptoms and also experiencing a brain fog that you just can’t shake. The most likely, point-A-to-point-B explanation is that the same inflammation your body is producing in response to allergens is also disrupting parts of your life that underlie stable mental functioning – especially sleep. Even just a handful of sleep disruptions each night can result in feelings of imbalance, loss of focus and exhaustion. The effects compound the longer that goes on, and the world starts feeling three shades of hazy.

Another possibility is that the inflammation is affecting your ears, particularly the drainage tube in the middle ear known as the eustachian tube. When the middle ear is unable to drain properly, the result is imbalance, dizziness and generally feeling like your head is under water.

Beyond those explanations, research has also probed what’s happening in the brain during an allergic response, and a few interesting findings have surfaced. One study examined the extent to which allergic rhinitis affects cognitive function (defined as “sustained attention, short- and long-term memory and speed of information processing”). The results showed that the brain compensates in the short term, but over time, as we suffer through allergic reactions, cognition significantly decreases. Allergies strain the brain, these results suggest, and key functions from attention to memory diminish the longer the battle rages.

Another study examined the brains of mice exposed to a common grass allergen. The researchers found heightened activity in the hippocampus, an area of the brain central to memory (in both mice and humans), but the activity wasn’t at all what they expected. They found that the allergens triggered growth of new neurons (a process known as “neurogenesis”), while at the same time deactivating immune cells called microglia. Since allergies are an immune response, finding immune cells going offline in a part of the brain is more than a little peculiar. The results didn’t lead to a clear conclusion, but they do strongly suggest that how the brain responds to allergens isn’t straightforward. While we’re experiencing a slew of outward reactions, much more is likely going on behind our itchy eyes.

More studies have examined the connection between allergies and mood, including depression, and correlations consistently appear, although drawing cause and effect conclusions remains difficult. Some evidence suggests that heightened inflammation triggers neurochemical changes leading to depressive episodes.

Whatever is causing the reactions, experts advise that controlling symptoms is the only way to cut through the fog. Antihistamines are the quickest way to go for most people, if you can handle the side effects that come with many of the drugs, like drowsiness and dry mouth. Newer, over-the-counter antihistamine inhalers are a good choice for those who'd rather not pop a pill everyday, and they also cover a range of symptoms.

Another way to go is to develop partial immunity to allergens through regular injections of what ails you. According to the American College of Allergy, Asthma and Immunology, “Immunotherapy (allergy shots) helps reduce hay fever symptoms in about 85% of people with allergic rhinitis.”

You can also try avoiding what sets you off (which might work if you’re mainly allergic to pet dander, assuming your friends are willing to keep their cat in another room), but for most allergy sufferers that’s not much of an option.

Whether it’s sleep disturbance, neurochemical changes or some combination of factors resulting in allergic brain fog, rest assured you aren’t imagining it – it’s real, and you aren’t alone. Do your best to control allergy symptoms by finding a treatment that works for you, and try to get enough sleep every night to avoid the effects of compounding sleep loss. Keep the tissues handy, we’ll get through this.

David DiSalvo is the author of "Brain Changer: How Harnessing Your Brain’s Power to Adapt Can Change Your Life" and the best-selling "What Makes Your Brain Happy and Why You Should Do the Opposite", which has been published in 13 languages. His work has appeared in Scientif...